1. Field of the Invention
The present invention relates to a dishwasher and a control method therefor. More specifically, the present invention relates to a dishwasher and a control method therefor capable of improving washing performance and drying performance by adjusting operation time of a heater according to turbidity of washing water.
2. Description of the Related Art
A dishwasher is a device washing contaminants such as food wastes adhering to dishes or cooking tools (in what follows, they are called “dishes”) by using a detergent and washing water.
The dishwasher comprises a main body including a washing tub; and a door opening or closing an opening part of the main body, a rack assembly where dishes are loaded, being disposed inside the washing tub; a sump in which washing water is stored, being disposed in a lower part of the washing tub; a washing pump pumping washing water stored in the sump; a washing motor driving the washing pump; and spray nozzles spraying washing water pumped from the washing pump to the washing tub. The dishwasher further comprises a heater for heating washing water. The heater can be installed inside the sump.
The operating sequence of the dishwasher comprises a preliminary and a main wash; rinsing and heated rinsing; and drying routine. At the time of the main wash and the heated rinsing, the heater is operated and thus, heated washing water is supplied inside the washing tub. If the washing motor is operated, the dishwasher pumps washing water from the sump. The pumped washing water is sprayed toward the rack assembly inside the washing tub through the spray nozzles, thereby washing or rinsing dishes put in the rack assembly.
However, conventional dishwashers maintain heating of washing water at a constant level irrespective of turbidity of washing water, limiting improvement of washing and drying performance.